The invention relates generally to power conversion, and, more specifically, to a single stage power conversion system.
With the rising cost and scarcity of conventional energy sources and concerns about the environment, there is a significant interest in alternative energy sources such as solar power and wind power. Solar power generation uses photovoltaic sources to generate electricity from the sun. Multiple photovoltaic sources are electrically coupled to one another in such systems. The electricity generated by photovoltaic sources is transmitted to the power grid through one or more power electronic converters. The power electronic converters are commonly classified as dual stage converters and single stage converters depending on the number of stages employed to convert direct current power to alternating current power.
Conventional single stage power conversion systems include a single stage converter connected to a controller that implements a maximum power point (MPP) algorithm to transmit maximum alternating power to the power grid from the single stage converter. Typically, a single stage power conversion system is controlled such that its performance can be compared to a stiff current source. In such current-stiff embodiments, the controller ensures that a direct current voltage, hereinafter DC voltage, is held at a desired value by guaranteeing that the power injected in the power grid matches the power obtained from the photovoltaic source. This is achieved by regulating a grid alternating current, hereinafter AC current, such that it follows any variation of the input power obtained from the photovoltaic source. Current stiff power conversion systems do not set a grid voltage. In solar applications it is desired to constantly adjust the DC voltage to extract maximum power from the solar array.
Therefore, it is desirable to determine a method and system that will address the aforementioned issues.